Multiple tundish system for metal refining plant



I 2 United States Patent l 13-,5;36,1,2-5

[72] Inventors MlchelJ i I New CR8! Doylemwn, and UNITED STATES PATENTS1 2,625,719 1/1953 Moore 164/25'8 Pawn 2,788,270 4/1957 Nisbet et al.266/34X [211 P 7 1968 1 2,983,973 v 5/1961 'Parlanti r 164/65 {221 13,008,855 11/1961 SWenSOn 164/61x [451 Palm 3,460,604 8/1969Tingquistetal. 164/61 [73] Assignee Pennwnltcurporaflon W u Zunqrygrammer-JkSgencer Oxlrholser m p i szs ta nt xaminerpencer nearAttorneys-Carl A. Hechmer, Jr. and Stanley Bilker A metal refining plantin which molten metal is poured from a tilting induction furnace in afirst vacuum chamber into molds contained within a second vacuum [54]SYSTEM FOR METAL chamber. The two chambers are interconnected by way ofa 8 D 1 horizontally operable valve disposed between the two cham- Chi,bers. A tundish which is movable in both a horizontal and a [52] US. Cl164/258, vertical plane directs the molten metal through the valve into164/65, 266/ l 3 a mold positioned therebelow. Means are providedto-preheat [51] Int. Cl. .l 322d 27/16 the tundish, and an auxiliarytundish is coupled to the first for [50] Field Search -l64/6l, 62, usein an emergency. All operations are controlled and visible 65.l33.254.256.258.337:266/l3,34(U) .1

from the exterior.

Patented jogt. 21, 1970 7' Sheet INVENTORS MICHAEL J. BLAS/(O gs/v ra'm'mwmwv I 14% rm/ma Patented Oct. 27, 1970 7 Sheet mnwraws MICHAEL J.ems/r0 HEW/U 0. HERRMA/V/V Pgten td Oct; 27, 19 70 Sheet v INVENTORSMICHAEL J. BLAS/(O ATTOR/VE'V MULTIPLE TUNDISH SYSTEM FOR METAL REFININGPLANT This invention relates to an apparatus and method for vacuumrefining of molten metals. More particularly, it relates to a vacuummetallurgical refining plant in which there are vertically adjoiningchambers interconnected through a valve. A tilting induction furnace islocated in the first chamber which is connected to suitable airevacuation means. One mold at a time is positioned beneath the valve. Amovable tundish which is adapted to be horizontally moved from apreheating staiton to a position over the valve can also be verticallylowered through the valve when the latter is in open position wherebythe molten metal may be directed from the furnace into the molds, allunder vacuum conditions. Anauxiliarytundishiscoupledtothefirsttundi'shandcanbeusedduring anyemergency.

Heretofore, during the vacuum refining of metals using inductionfurnaces, it has been the practice to melt and pour the molten metalinto molds all within a single vacuum chamber. As a consequence, onecould not recharge the furnace nor remove the molds without breaking thevacuum. Accordingly, the operation became inefficient since the furnacecould not be used to refine a fresh charge of metal while the molds werecooling, nor could molds be moved into the vacuum chamber while the meltwas being degassed in the furnace. It was therefore necessary to performthe melting and refining operation in a first chamber, pour the moltenrefined metal into a ladle or other suitable carrying device, and thenmove the ladle into a second separate and independently operated chamberin which the molten metal was teemed into molds. While mold tunnelinterlocks have been employed, these not only required large door valvesthrough which the mold cars could pass but also they consumedconsiderable floor space.

It is therefore an object of this invention to provide an apparatus andmethod for vacuum refining and pouring metal into molds simultaneouslywithout interfering with the recharging of the furnace while the moldsare cooling or the removal of the molds while a fresh batch of metal isbeing refined.

Another object of this invention is to provide a metallurgical refiningplant in which refined molten metal can be poured through a conduitdirectly into molds while the entire system is under vacuum.

Still another object of this invention is to provide a vacuummetallurgical refining plant which employs a tundish system to directmolten metal from an induction fumace through an intermediate valve intomolds so as to minimize floor space and enable minimal size valvecomponents to be utilized.

Yet another object of this invention is to provide a mobile tundishsystem in which an auxiliary tundish is attached to the main tundish andis adapted to be immediately employed in the event of an emergency, suchas failure of the main tundish.

Still yet another object of this invention is to provide a means forpreheating a tundish preparatory to its use for directing molten metalinto molds.

A further object of this invention is to provide a dual-chambered vacuummelting and molding plant in which an intermediate valve is used tointerconnect the refining and molding chambers in combination with amobile tundish which can be conveniently positioned at a preheatingstation, at an inactive station, or at a pouring station.

Yet a further object of this invention is to provide a mobile tundishsystem for a valved dual-chambered vacuum refining and pouring plant inwhich the valve sealing elements are fully protected from molten metaldrippings and heat radiations.

Still yet a further object of this invention is to provide adual-chambered vacuum metallurgical refining plant in which the pour andteeming operations are all visible and operable from a single remoteexternal station.

Yet still another object of this invention is to provide a dualchamberedvacuum metal refuting plant in which all refractory elements areconveniently exposed for maintenance.

Other objects of this invention are to provide an improved device of thecharacter described which is easily and economically produced, which issturdy in construction both highly efficient and efl'ective inoperation.

With the above and related objects in view, this invention consists ofthe details of construction and combination of parts as will be morefully understood from the following detailed description when read inconjunction with. the accompanying drawings in which:

FIG. 1 is an elevational sectional view of a metallurgical refiningplant embodying the instant invention. I

FIG. 2 is a sectional view taken along lines 24 of "1.

FIG. 3 is a sectional view taken along lines 3-3 of 2.

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 2.

FIG. 5 is a sectional view taken along lines 5-5 ofFIG. 4.

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 4.

FIG. 7 is a sectional view taken along lines 7-7 of FIG. 6.

FIG. 8 is a sectional view taken along lines 8-8 of FIG. 7.

Referring now in greater detail to the drawings in which similarreference characters refer to similar parts, we show a vacuum refiningapparatus comprising a melt chamber A having a metal refining furnace Benclosed therein, a mold chamber C or tunnel for holding molds D, avalve E interposed between the two chambers, and a movable tundishassembly, generally designated as F, which is adapted to direct metalpoured from the fumace B into the molds D through the valve Ethereabove.

Referring especially to FIG. 1, the melt vacuum chamber A is areinforced steel housing and includes a lower section 12, a portion ofwhich rests upon a structural bed 14. A cover 16 is detachably securedover the lower section 12 by a suitable flanged coupling 18 and can berolled back to expose the contents thereof. The chamber A is ofsufiicient cubic dimensions to support and enclose the furnace B and isconnected by a conduit 20 to an air evacuation means, such as amultistage, steamjet, high vacuum system (not shown). A suitable valvedhopper 22 is mounted in the cover 16 so that the furnace B may chargedunder vacuum, if it is so desired. The furnace B may be any suitablehigh-temperature melting device for heating, melting, stirring, andrefinning metal, such as steel, under high temperature conditions.Preferably, it is a careless induction furnace because of compatabilitywith an evacuated environment and by virtue of its ability to producestirring as well as heating by eddy current developed thereby. Thefurnace B includes a generally cylindrical crucible 24, of 30-toncapacity for example, which has a pouring lip or spout 26. Suitablerefractory lines the entire interior of the furnace.

The furnace B is supported by means of trunnions 28 laterally extendingtherefrom and pivotally supported in pillow blocks 30. I-Iydraulicallyactuated drive means (not shown) enables the furnace to be tiltedforwardly approximately for pouring molten metal into the tundish F.Means are also provided to back tilt the furnace approximately 30 from avertical for cleaning and/0r maintenance purposes.

The mold tunnel C is also a reinforced structural steel chamber which isseparated from the melt chamber A by a vertical partition wall 32 and bya horizontal deck 34. A conduit 21 couples the mold tunnel C also to theair evacuation means through suitable valving (not shown) whereby vacuummay be applied to either the mold tunnel or the chamber A independently.The valve E is incorporated in the deck 34 so that a mold assembly D maybe oriented directly under the valve aperture. A platform 36 is disposedoutside the melt chamber A at approximately the level of the deck 34whereby operating personnel at a single location can convenientlyobserve the pour from the furnace B into the tundish F through sightport 38 and the teeming from the tundish into the-molds D via sight port40.

The tundish amembly F is best illustrated in FIGS. 2 and 4. It includesa pair of side-by-side refractory lined channel members 42 and 44, thetundish 42 being used for normal operations and tundish 44 being anauxiliary standby or emergency unit. Each includes a generallycylindrical splash shield 46 at one end into which the molten metal ispoured fiom the lip-26 of the B. A spout 48 at the otherendgconveniently funnels the molten metal flow into a stream. Weir 50interposed at the downstream side of the tundish allows the molten metalheat to be skimmed of surface contaminants.

The operating tundish.42-and the auxiliary tundish 44 are 1 bothsupported a pie-shaped holder or rack 52 Concave rollers 53 and 54journaled in bearings 56 at the bottom 1 of the rack'52 engaged withandride upon a liquid cooled arcuate pipe rail 58 which is supported on thedeck 34.

The other end of the rack 52 includes an arm 60 which projects throughopposed slots 62 and in cylinder member '66. The arm 60 rests on abutton68 supported on the upper end of a piston 70 which is verticallyreciprocable in the lower closed I end of cylinder 66. A thrust bearing72 rotatably supports the lower end of cylinder 66, the upper portion ofwhich includes a shaft 74 journaled in bearing 76. Rotatable motion oftundish F assembly about an definediby bearings -72and 76, is producedby rotation of pinion whichis in engagementwith bevel gear 82; onbevelgear 8 2 is jo'ur-,

naled in a sealedtbearing 86 mounted in the circumferential at theopposite endof shaft 84 outsideof the chamber A and supported belowskulling platform 90 forrotating' the tundish.

F'either in a clockwise or counterclockwise direct ionas wall 12 ofchamberA. .A motor drive unit its-+89 is mounted:

spout 48. Itis also to be noted that the F may beraised by elevation ofpiston 70 so as to stop the flow-of molten metal through the nozzleatter filling each mold. The valve E may now beclosed whereupon can berecharged under vacuum or brought up toatnrospheric conditions byrolling back the cover Skullingofthe furnace can be ac- V complished atthis stage while the molds arecooling under vacuum. Conversely, whilethe'rnelt in the furnace is being refined under vacuum the molds can betaken out of themold r tunnel C without interfering with] operationsinthe melt chamber.

is to be observed that by locating the valve E in a horizon- ,talposition vertically separating the two chambers A and C,

theteeming through the spout 48 is vertical. At the same time,

' all ofthe refractoring in both the tundish F and the fumace'B 'isfully expressed for convenient cleaning when just the cover 44 isavailable for immediate service.

Although this invention has been described in considerable detail suchdescription is intended asbeing illustrative rather than limiting sincethe invention may be variously embodied,

l6.is rolled back. In the event of failureoftundish 42, tundish and thescope of the invention is to be determined as claimed.

7 v 25" desired. Shield 92 acts to protect the bevel andpinion from anysplashing metal and/or radiant heat. The operator standing on thepouring platform 36 can observe pouring of the metal from the furnaceAinto the tundish F byway of sight port 38 or from the. tundish intothe'moldsby way of sight port The isolation valve E is essentially alarge horizontally actuated water-cooled gate valve which is interposedwithinfan best generally illustrated in FlGS. l,2. arid 4..l'he detailsof construction of the valve E are best seen in FlGS. 6, 7, arid 8.

The valve E includes a housing portion which includes o pposedflanges'102and 104 for couplingto conduit fittings. in this caselflange'102 is'bolted to'a complementaryring94 mountedwithin the deck opening.Flange 104 may have a opening in thedeck 34 between the two chambersjAand C, as l cover 'plate96 pivotally connected thereto which maybe swungout of the way when the tundish spout 48 is inserted. A

heat shield 98 is coupled to the ring .94 and tapers upwardly to r anorifice somewhat. larger than thatof the tundish spout. The

valve E'is operated by a do uble-acting hydraulic cylinder 106 whosepistonis connected to valve plate 108 through rod 110,. guiding block112 and levers 114. Draw springs 116 connect ing. the valve plates 108prevent the letter from slidingonthe inside of the housing. wall 100duringhorizontalin-and-out movement. When opening, the'valve plate'isfirst lifted from its seat before it is moved aside. A'heat shield 118overlies the. 'surface of the valve plate toguard it-from radiation. The

: means for moving molds into and out of said second clmmber' piston rodis sealedagainst vacuum by an oil 120;

, Suitable reinforcing ribs 121 insure the. maintenance of tundish F maythenbe swung in a horizontal plane until it situated under a canopy 122defining a preheating stationQA series of nichrome, heat elements 124'serve to elevate the tundish to a temperature wherein its refractorywill not be appreciably shocked and so that themolten metal being pouredwill not sufier too great a cooling effect during pouring.

The furnace chamber-A is pumped down with the valve E closed. .Molds Dare run into the mold chamber C which pumped down to thesame vacuumasthat in the chamber before the melt is poured. The valve E is openedthe tundish F rotated until in'approximate registration with thefurnace. The tundish spout 48 is=next loweredthrough thevalveEr r r Froma position outside the chambersA and C, the operator on platform 36tilts the-furnace B forwardlywhile observing the pour through sight'port'38. Teerning. from the tundish into, V the mold D isvisiblerthroughl sightport 40..When all of the I molrk have been iselevatedto 55. p r As is apparent from the foregoing description, thetundish F molten metal is poured therethrough. 1

" 3. The apparatus of claim 1 wherein said conduit means comprises afirst tundish for performing the pouring operations and a second tundishcoupled thereto for standby emer- We claim: i l. Metallurgical. refiningapparatus comprising a first chamber including fumace means formeltingand refining metal therein, a second chamber'including ahorizontal portion extending at least partially within said firstchamber, valve means interposed within said horizontal portion forisolating said first and second chambers fromeach other, means foropening and closing said valve means, means for'evacuating r said firstand second chambers, conduit means including an inlet end for receivingmolten metal from said fumace means, an intermediate channel portion fordirecting the-molten metalalong a substantially horizontal path, and adischarge end for vertically teeming the molten metal into a moldlocated'therebelow, vcarriagev means supporting said conduit 1 means insaid first chamber, first drive means for horizontally orienting saidcarriage means at a pouring position in which the inletof conduit meansis in registration with metal being poured from said furnace and saiddischarge end is in registration with said valve means-, second drivemeans for vertically displacing the discharge end of said conduitmeansfrom an elevated position over'said valve to a lowered positionextending through said valve r when open, and

andaligning one mold ata time under the discharge end of said conduitmeans, whereby said first and secondchambers berindependently andinterdependently operated under ,vacuumconditions'. j. 2. Theapparatusof claim 1 including a heating station 1 means in said firstchamber horizontally displaced from said pouring position. forpreheating said conduit means before gency operations in the event offailure at 'said first tundish.

4. The apparatus of claim 1 wherein said carriage means is pivotallysupported about vertical and horizontal axes. r

5; The apparatus of claim 4 wherein said carriage means includes anarcuate rail disposedin a horizontal plane, and

means constituting rollers engaging said rail.

I v 6.,The apparatusofclaim 5 wherein said roller means de- 65;

Z stituting a rotatable cylinder embracing the other end of saidcarriagemeans. P

1 7. apparatus of claim 6 including a piston in said rotatable cylinderengaging said other end of said carriage means.

' 8. The apparatus or claim 1 w rein said valve meam con- .pend from oneend of said carriage means, and means constitutes a gate valve.

9The apparatus of claim 11 in which of said means are j operable from aposition extemal-to said'chambers.

10. The apparatus of claim 9 including means to view the pouring andteeming operation from a single station external to said chambers.

